A stacked memory package is configured such that memory chips (which are memory devices) are stacked and encapsulated with a mold resin, and is used while being mounted on a board.
After the stacked memory package is mounted and starts to be used, an interconnection in the stacked memory package may be broken, which results in that the stacked memory package cannot be driven. In this case, data stored in the stacked memory package cannot be read and the data is lost.